Sleeper: ReDim a type

[athom]

Hi there,
I'm using type to store data in my VBA code. I start with the usual declaration:

Type BeamType
        TotNo As Long
        No(200) As Long
    End Type

I then assign a variable to this type:

    Dim Beams As BeamType

How do I change the array size in my code though, I tried ReDim like:

    ReDim Preserve Beams.No(1 To 20) As Long

But that just produces an error.
Any Ideas?